The fill-in-the-verb cards follow the KOFI method from Lisardo's Ultimate Spanish Conjugation deck. Each tense gets one fixed cue (Ahora mismo… for the present, Fue sorprendente que… for the past subjunctive), so the cue alone tells you which tense to reach for. The cue phrases and the deber command dialogues are taken from that deck. If this course helps you, its deck is the natural next step, because it covers the irregular verbs.
The explanations, translations and the four-verb structure were written for this course. The conjugations of hablar, deber and vivir were checked form by form against the KOFI deck.